Re: [OSR-devel] Speeding up mkinitrd

[Gordan B. <go...@bo...>]

Gordan Bobic wrote:

> 2) Compression speed
> 
> 2.1) Using a parallel gzip (http://www.zlib.net/pigz/) compressor, which
> should scale pretty much linearly with the number of CPU cores. A (source)
> RPM seems to be available, but only for SuSE
> (http://rpm.pbone.net/index.php3/stat/4/idpl/11044884/com/pigz-2.1.4-5.1.x86_64.rpm.html),
> so until it is more common, it may have to be made available via the
> comoonics yum repository.

OK, that was 100% pain-free. The SuSE src.rpm compiles cleanly on 
RHEL/CentOS 5.x. The performance scaling is completely linear (32 
seconds with gzip on a quad core Core2, 8 seconds using pigz).

The resulting compressed files aren't identical (pigz one is actually a 
tiny bit smaller), but when they are ungzipped (ungzipping works using 
standard ungzip), the decompressed files are the same, so it seems safe 
enough. :)

Even without any further boosts in compression speed, this seems pretty 
worthwhile, and it has the advantage of being 100% clean, OSS, and 
extremely painless to implement (whereas ICC will involve opening a 
whole new can of worms for a much smaller benefit).

So, if I may be so bold to ask - any chance of including pigz in the yum 
repository and adding a dependency on it for the comoonics-bootimage?

I'd submit a create-gfs-initrd-lib.sh patch, but I can't help but feel 
that a patch as small as 2 lines would be a bit lame. :^)

Gordan